OBJECTIVES: Many patients with overactive bladder (OAB) treated with anticholinergic medications (AM) continue to experience urinary symptoms; some may be candidates for specialized treatment including sacral neuromodulation (SNM). This analysis determined AM costs in OAB patients who were enrolled in the InSite study.  METHODS: Subjects who failed >1 AM and were candidates for SNM were enrolled in a prospective, multicenter trial.  For patients receiving SNM, AM use was not permitted during the first 6 months.  Thereafter patients could use medication if needed.  Patient-reported AM cost at 12 months post-implant, based on an economic impact questionnaire inquiring about AM cost over the past 2 months, was compared to baseline.  AM cost at baseline and 6 months for a separate cohort randomized to standard medical therapy (SMT) is included for comparison. RESULTS: Of 231 SNM patients, 207 had baseline and follow-up data, of which, 74 (35.7%) reported baseline AM costs >$0. Of 74, 4 (5.4%) reported AM costs at 12 months.  Of 133 patients with $0 baseline cost, five (3.8%) reported AM cost >$0 at 12 months.  Of the 207, the average cost/patient over a 2-month period was $178 at baseline and $14 at 12 months post-implant. Of 75 SMT patients, 68 had baseline and follow-up data, of which, 28 (41.2%) reported baseline AM costs >$0. Of 28, 19 (67.9%) reported AM costs at 6 months. Of 40 patients with $0 baseline cost, 11 (27.5%) reported AM cost >$0 at 6 months. Of the 68, the average cost/patient over a 2-month period was $176 at baseline and $218 at 6 months. CONCLUSIONS: For patients receiving SNM, the average AM cost/patient markedly decreased by 92.1% at 12 months. Reductions were not seen for patients receiving SMT, where the average AM cost per patient increased by 23.9% at 6 months.